Control apparauts



Apr. 10, 1923 1,451,544

R. E. HELLMUND CONTROL APPARATUS Filed Apr. 9, 1919 2 sheets-sheet 1 WITNESS-ES: INVENTOR a W fiuaa/fl-le/lmund,

. 7 BY I ATTORNEY Apr. 10, 1923 1,451,544 R. E. HELLMUND CONTROL APPARATUS Filed Apr. 9, 1919 2 sheets-sheet 2 A5 "/5 .4 5 YE I 3a a WITNESSES: INVENTQR 1%] WW Ruao/f E. fiel/mu/m 7 7 ATTORNEY Patented Apr. 10, 1923.

RUDOLF E. HELLMUND, F SXVISSVALE, PENNSYLVANIA, ASSIGNOR TO HOUSE ELECTRIC &, MANUFACTURING VANIA.

WESTING- COMPANY, A CORPORATION OF PENNSYL- CONTROL APPARATUS.

Application filed April 9,

To all whom it may concern Be it known that I, RUnoLr E. HELLMUND, a citizen of the German Empire, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Apparatus, of which the following is a specification.

y invention relates to control apparatus for electric motors and the like, and

and it has special relation to the interlocking or" cam-operated switching devices.

One object of my invention is to provide a relatively simple apparatus or" the 1 above-indicated character for automatically preventing the simultaneous closure of two switches.

More specifically stated, it is the object of my invention to provide a plurality of valve members that are operated by cams to closed positions, together with an electrical interlock upon a switch that is governed by one of the valve members for restraining the opening movement of another member when the switch provided with the interlock occupies its closed position.

Other objects of my invention will become evident from the following detailed description, taken in conjunction with the accompanying drawing, wherein Fig. 1 is a view, partially in section and partially in elevation, of a complete. switching device constructed in accordance with my invention, and Fig. 2 is a diagrammatic view of the interlocking apparatus and circuits that are employed in carrying out the principles of the invention.

In control systems for electric railway motors, for example, it is necessary to provide some form of interlocking between certain switches, to prevent a simultaneous closure thereof which would result in an undesired short circuit of a motor or of a supply-line, as will be appreciated by those skilled in the art. Unless such interlocking is provided, it is possible for one of such switches to freeze, or stick in aclosed position, when the sequence of operation would normally cause the switch to return to its open position. Under such conditions, the closure of some other switch would create the above-mentioned shortcircuit, and it is to prevent such simultane- 1919. Serial No. 288,797.

ous closure of two cam-operated switches that I provide the present simple electrical interlocking scheme.

It will be understood that the configuration of the various cams will provide the desired sequence of operation, under ordinary conditions, and that no further interlocking is necessary for this purpose, whereas be present invention is designed to provide necessary preventive interlocking for safety purposes.

Referring to Fig. 1 or" the drawing, the switching apparatus 7 here shown is of a familiar general construction, and comprises, essentially, av stationary contact terminal 1, a co-operating movable which is actuated by a fluid-pressure mechanism 3 to also control the actuation of an auxiliary-circuit cont-actor or interlock 4, the operation of the fluid-actuated mechanism 3 being directly controlled by a movable valve device 5, which, in turn, is governed by a rotatable cam member 6.

Inasmuch as the particular structure of the contact terminals 1 and 2 is immaterial to my present invention, and may be of any well-known form, I do not deem it necessary to further describe these terminals. The fluid-actuated mechanism 3 is likewise of a familiar type, comprising a rod or stem 10 that is suitably connected to the movable contact terminal 2, and the lower end of which constitutes a piston 11 that operates within a cylinder 12 and is biased towards the i-lustrated lower position by means of a coil spring 13 within the cylinder.

The rod 10 is provided with a laterallyextending arm 14 which carries a suitable insulating block, upon which the movable contact member 15 of the electrical interlock 4 is mounted, to engage a plurality of auxiliary control fingers 16 in one of the positions of the switch.

The valve device 5 is shown as comprising a coil 17 that is employed for interlocking purposes to be set forth, being adapted, when energized, to attract upwardly a plunger or a slidable core 19, an intermediate portion of which constitutes a valve member having an upper plug 20 and a lower plug 21 for alternatively occupying closed positions in a valve seat 22. The lower end release of fluid pressure of the core member 19 extends outside of the valve casing and terminates in a roller 23 which makes contactwith a cam 2 1 that is suitably secured to a rotatable controller shaft 25. A helical spring 26 biases the core 19 downwardly to maintain engagement of the roller23 with the cam 24.

Fluid pressure from any suitable source (not shown) is admitted'below the valve seat 22 through a suitable inlet pipe or passage 27 to a supply passage 28 communicating with the operating cylinder 12 when the valve plug 20 occupies its seated position corresponding to the occupation of the recess 30 inthe cam 2-1 by the roller 23, or, in other words, corresponding to the biased lower position of the valve core 19. In the illustrated position of the cam 24, the supply passage 28 communicates with the atmosphere through an outlet port 29, while the piston 11 occupies its biased lower position and the switch terminals 1 and 2 are open or out of contact.

To effect the closure of the contact terminals 1 and 2, the cam 24 is ually or otherwise, into a position wherein the recess 30 receives the roller 23,v to which position the roller is biased by the spring 26.

Under such conditions, fluid pressure is admitted from the inlet pipe 27 through the valve seat 22 and supply passage 28 to the operating cylinder 12, whereby the piston 11 is forced to its uppermost position against the action of the spring 13 to effect suitable contact of theswitch terminals 1 and 2. Such movement of the piston likewise carries the movable interlock contact member 15 into engagement with the stationary control fingers 16.

To effect the opening of the switch, the cam 24 is rotated into the illustrated position, or its equivalent, to return the valve core 19 to its illustrated position in opposi tion to the spring 26 and thus permit the from the operating cylinder through the outlet port 29' to the atmosphere, whereupon the spring 13 effects the desired movement of the piston 11 to the position shown, and the switch terminals become disengaged.

Referring to Fig. 2, a plurality ofswitching devices 7 and 3 1 are shown in a simplified manner, the switch 7 comprising all of the various elements that are illustrated in Fig. 1, while the switch 34; "is of similar construction, with the exception of the omission of the actuating coil-17.

An'auxiliary source of energy, such as a battery B, and a controlling apparatus MC of the familiar master controller type, are also shown to illustrate the electrical interlocking feature of the present invention. It will be appreciated, however that only the minimum essential number of elements, has

been shown and that the customary complete ply passage 28to t actuated, manuthe engagement of '21 for the switch 7,

governing system will be employed, with the addition of the novel features of -my present invention.

Assiuning that the switch M has been closed through the agency of the cam 35, which, in accordance with-the usual practice, is mounted upon the same shaft '25 as the other cam. member 6, fluid pressure will be exhausted from the operating cylinder of the switch 34; (not shown) through the supe atmosphere, in accordance with previously described operating principles. Consequently, the switch 34 should open to 'allow the subsequent closure of the switch 7, it being assumed that'the simultaneous closure of the two switches 7 and 3% would cause an undesirable shortcircuit, as hereinbefore,mentioned.

However, if the switch 34 freezes in its closed position, then the interlock 4; 'will'remain in' itsup-per position corresponding to the engagement of the auxiliarycontact members 15 and 16, although the valve plug 21 occupies its non-corresponding or closed position wherein the interlock contact 'members 15 and 16 arefnormally disengaged.

If it is attempted to close the switch 7 under such frozen conditions 'of the switch 34:, the controller shaft 25 may, of course, be actuated to a position corresponding to the position of the cam member in Fig. 2, but the biasingfspring 26 is ineffective to cause the valve core 19 to assume 'its'lo'wer position seating the plug 20, by reason of the fact that the core 19 is now "magnetized by the actuating coil 17 and is thus held in its upper position to prevent the access of fluid pressure to the supply passage28,' and, consequently, the closure of the switch 7.

The energization of the actuatingv coil just mentioned is effected by the establishment of a circuit from the positive terminal 'of the battery B through conductor 36, control fingers 37 and 3 8, which are bridged by'contact segment 39 of the master controller, in' position a, for example, (which corresponds to the previous closure of the switch 3 1), whence circuit is continued through condu'ctor 1:0, cont-act members 16 and 15 of the interlock l, conductor'tl, actuating'coil 17 for the switch 7 ,and conductor 12, to the negative battery terminal. In other words,'fas long as the switch 34 is frozen, to maintain the contact membersl5 and 16 in the upper position of the interlock l, the opening movement of the valve plug to produce the closure of that switch, cannot be effected, by'reason of the electrical 'r'estrainingaction of the 'actuatingcoil 17, which maintains the valve member in the position that is illustrated in Fig. 2, irrespective of the fact" that the cam 6 occupies the position that corresponds to the closure of the switch.

It will be appreciated that, if desired, the

pneumatic type of switch illustrated may be replaced by a straight cam-operated switch, and that the principles of the present invention may be readily applied thereto, in the light of the foregoing description. Other modifications may likewise be made in the illustrated structural details, control circuits, and arrangement of parts, and I desire, therefore, not to be restricted to the specific embodiment of my invention that I have shown, but that only such limitations shall be imposed thereupon as are indicated in the appended claims.

I claim as my invention:

1. The combination with a plurality of movable control members, of means for mechanically actuating the first of said members to a certain position, and means normally responsive to the position of a second member for itself electrically preventing the return movement of the first member.

2. The combination with a plurality of movable control members, of means for mechanically actuating the first of said members to a certain position, a device normally controlled by a second member, and means for preventing the return n'ioven'ient of said first member unless said device occupies a normal position.

3. The combination with a plurality of movable control members, of means for mechanically actuating the first of said members to a closed position, a device normally controlled by a second member, and electrical means acting on said first member for preventing the opening movement thereof when said device occupies a closed position.

4. The combination with a plurality of movable valve members *iased toward an open position, a plurality of cam members for actuating the respective valve members to closed positions. a device normally controlled by the first of the valve members, and means for electro-magnetically restraining the opening movement of a second valve member if said device has been closed through the agency of the corresponding cam member.

5. The combination with a plurality of movable valve members biased toward an open position, a plurality of cam members for actuating the respective valve members to closed positions, an actuating coil for one of the valve members, and an interlock associated with the other valve member for energizing said coil to prevent the opening movement of the corresponding valve memher under predetermined operating conditions.

6. The combination with a plurality of pneumatically-actuated switches and a plurality of valves therefor, of means for mechanically actuating said valves, and means responsive to the closure of one switch for electrically preventing closure of another irrespective of the position of said actuating means.

7. The combination with a plurality of pneumatically-actuated switches and a plurality of valves therefor, of cam members for actuating said valves, a coil for preventing the actuation of one of the valves, and an interlock upon the other valve for energizing said coil under predetermined relative conditions of the valves.

8. The combination with a plurality of pneumatically-actuated switches and a plurality of valves therefor, of cam members for releasing said valves to effect closure of the switches, a coil for preventing the actuation of one of the valves. and an interlock; upon the other valve for energizing said coil to prevent closure of the corresponding valve and switch when the other switch is frozen.

In testimony whereof. I have hereunto subscribed my name this 27th day of March, 1919.

R-UD OLF E. HELLMUND. 

